const str = 'bar=foo&arr[1]=8&arr[0]=9&obj={"a":"hellow","b":"word"}'
// bar%3Dfoo&arr%5B1%5D%3D8&arr%5B0%5D%3D9&obj%3D%7B%22a%22%3A%22hellow%22%2C%22b%22%3A%22word%22%7D
// console.log(encodeURIComponent(str));
// const obj = {
//     bar: foo,
//     arr: [9, 8],
//     obj: {
//         a: 'hellow',
//         b: 'word'
//     }
// }
console.log(decodeURIComponent('arr%5B1%5D%3D8&arr%5B0%5D%3D9'));